From e783bf8aed6b1943c7c46a390e2bdbaef52225e5 Mon Sep 17 00:00:00 2001
From: Peter Bengtsson <peterbe@mozilla.com>
Date: Thu, 4 Oct 2018 22:42:16 -0400
Subject: [PATCH] avoid TypeError on when registering service workers without
 config (#5301)

* avoid TypeError on when registering service workers without config

Fixes #5299

* same before config.onUpdate
---
 packages/react-scripts/template/src/serviceWorker.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/react-scripts/template/src/serviceWorker.js b/packages/react-scripts/template/src/serviceWorker.js
index 8859a0c6..46c98a44 100644
--- a/packages/react-scripts/template/src/serviceWorker.js
+++ b/packages/react-scripts/template/src/serviceWorker.js
@@ -68,7 +68,7 @@ function registerValidSW(swUrl, config) {
               console.log('New content is available; please refresh.');
 
               // Execute callback
-              if (config.onUpdate) {
+              if (config && config.onUpdate) {
                 config.onUpdate(registration);
               }
             } else {
@@ -78,7 +78,7 @@ function registerValidSW(swUrl, config) {
               console.log('Content is cached for offline use.');
 
               // Execute callback
-              if (config.onSuccess) {
+              if (config && config.onSuccess) {
                 config.onSuccess(registration);
               }
             }